MRI using k-space spiral trajectory is a fast imaging method that is very flexible, and allows for changes in sampling density of the trajectory at different k-space locations. Because motion artifacts mostly come from inconsistencies between different k-space views and most of the energy for normal objects are concentrated in the center of k-space, motion artifacts can be reduced if the center of k-space is sampled more densely in each view. The goal of our research is to investigate the feasibility of a variable-density and piecewise spiral trajectory approach to reducing motion artifacts in MRI. Methods and Results We have designed several variable-density spiral trajectories. These trajectories were first tested by simulations to understand the possible effects on the motion artifact reduction. After simulation, the thorax of human volunteers were imaged and the images were compared. Results showed that the motion artifacts were greatly reduced using the variable-density trajectories. Discussion The flexibility of the variable-density spiral trajectory is enormous, and we are focusing on the effect of changing sampling density in order to achieve the best motion reduction result. The possibilities provided by the new, high-performance system are also great, and we are in the process of incorporating new features into the piecewise spiral trajectory to meet this potential.